The invention relates to the field of providing video information for display by a video display device, and more particularly to systems and methods for providing a translucent region for use in connection with, for example, a video program displayed on a video display screen. The translucent region may be used to provide, for example, enhanced contrast to facilitate easier viewing of a second image, such as a static or dynamic graphical image, on the same video display screen the one on which the video program is displayed.
In many environments, it is desired to be able to display, on a video display screen, such as a television receiver or the like on which one image is displayed generally over the screen, a second image which would, for example, occupy a relatively small region of the video display screen. For example, while a viewer is watching a video program such as one obtained over, for example, broadcast, cable, video disk, or other video program source, in the art, it may be desirable to enable the video display device to display information that, for example, relates to the video program being displayed on the video display, including, for example, the name of the program, the source of the program, and the like. Alternatively, it may be desirable to enable the video display device to display other video program information, such as, for example, program schedule information for broadcast or cable, disk menu information if the program source is a video disk, and the like. As another alternative, the information to be displayed may have no relation to the program being displayed. Such information may, for example, be provided from sources selected by the viewer. and may, for example, provide a notification as to the current time and date, indicate current prices of selected stocks, notification of the status of selected features of the viewer""s home or other viewing environment, a notification that a telephone call is being received, a notification that an Email message has been received, or any other information that a viewer may wish to have. displayed. This information may be provided in textual form, with the text being shown on the video display screen as a graphical image. Additionally or alternatively, the image may be in non-textual form, such as a graphical icon. The information provided by the image may also be fixed or variable.
The graphical image displayed as the second image as described above may be displayed directly over the video program. However, to, for example, improve the visibility of the graphical image and increase the contrast thereof over the program, it is generally desirable to provide a translucent region in which the graphical image is displayed. In the translucent region, a portion of the video program in the area around the graphical image is obscured, that is, it is not as bright as the program as displayed outside the translucent region. This allows for enhanced contrast between the graphical image and the surrounding display, which, in turn, allows the graphical image to be more easily viewed.
In the past, special hardware has been used to provide translucent regions and graphical images for display by a video display device along with a video program. The special hardware includes two frame buffers, and an xe2x80x9calpha blendxe2x80x9d hardware device. Each frame buffer stores information to be displayed by the video display device in digital form. One of the frame buffer is used to store the program to be displayed. The other frame buffer stores the graphical image. For each pixel to be displayed by the video display device, the alpha blend hardware device controls retrieval from one or both frame buffers to obtain pixel information for the program, graphical image, or both, and displays the translucent region and graphical image along with the video program.
The invention provides a new and improved system and method for providing a translucent region in a video program for, for example, providing enhanced contrast for graphical images superimposed thereover, for display by a video display device such as a television receiver or the like.
In brief summary, a system constructed in accordance with the invention generate a video signal defining an image for display by a video display device, the video display device displaying at least one image on a video display screen providing a plurality of pixels generally arranged in a plurality of rows. The system comprises a frame buffer, an averaging device, a video signal generator, and a control module. The frame buffer has a plurality of storage locations each configured to store a pixel value, respective storage locations being associated with pixels displayed by the video display device. The averaging device, which in one embodiment is a flicker filter, is configured to receive pixel values from a plurality of storage locations and generate therefrom an average pixel value according to a predetermined function. The video signal generator is configured to receive the average pixel value and generate the video signal therefrom for use by the video display device. The control module is configured to:
i. enable pixel values to be stored in the frame buffer, the pixel values comprising,
(a) outside of a translucent region to be displayed on the video display screen, image information for the image, and
(b) within the translucent region, in storage locations associated with alternating rows of pixels, image information for the image, and in storage locations associated with rows between the alternating rows of pixels, a predetermined pixel value; and
ii. enable pixel values to be retrieved from the frame buffer for use by the averaging device, the control module being configured to enable, for each average pixel value to be generated, pixel values from proximate rows to be retrieved so that, when an average pixel value is generated for a pixel within the translucent region, the average pixel value is the predetermined function of a pixel value comprising image information for the image and the predetermined pixel value, thereby to provide the translucent region.